ASP.NET MVC 4 Web API Authentication with Membership Provider

You could use basic authentication with SSL. On the server side we could write a custom delegating handler which will verify the credentials by querying the memebership provider that we registered, and if valid, retrieve the roles and set the current principal:

public class BasicAuthenticationMessageHandler : DelegatingHandler
{
    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var authHeader = request.Headers.Authorization;

        if (authHeader == null)
        {
            return base.SendAsync(request, cancellationToken);
        }

        if (authHeader.Scheme != "Basic")
        {
            return base.SendAsync(request, cancellationToken);
        }

        var encodedUserPass = authHeader.Parameter.Trim();
        var userPass = Encoding.ASCII.GetString(Convert.FromBase64String(encodedUserPass));
        var parts = userPass.Split(":".ToCharArray());
        var username = parts[0];
        var password = parts[1];

        if (!Membership.ValidateUser(username, password))
        {
            return base.SendAsync(request, cancellationToken);
        }

        var identity = new GenericIdentity(username, "Basic");
        string[] roles = Roles.Provider.GetRolesForUser(username);
        var principal = new GenericPrincipal(identity, roles);
        Thread.CurrentPrincipal = principal;
        if (HttpContext.Current != null)
        {
            HttpContext.Current.User = principal;
        }

        return base.SendAsync(request, cancellationToken);
    }
}

We then register this handler in Application_Start:

GlobalConfiguration.Configuration.MessageHandlers.Add(
    new BasicAuthenticationMessageHandler()
);

Now we could have an Api controller that will be decorated with the [Authorize] attribute to ensure that only authenticated users can access its actions:

[Authorize]
public class ValuesController : ApiController
{
    public string Get()
    {
        return string.Format("Hello {0}", User.Identity.Name);
    }
}

Alright, now let’s look at a sample client:

using System;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;

class Program
{
    static void Main()
    {
        // since for testing purposes I am using IIS Express
        // with an invalid SSL certificate I need to desactivate
        // the check for this certificate.
        ServicePointManager.ServerCertificateValidationCallback += 
            (sender, certificate, chain, sslPolicyErrors) => true;

        using (var client = new HttpClient())
        {
            var buffer = Encoding.ASCII.GetBytes("john:secret");
            var authHeader = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(buffer));
            client.DefaultRequestHeaders.Authorization = authHeader;
            var task = client.GetAsync("https://localhost:44300/api/values");
            if (task.Result.StatusCode == HttpStatusCode.Unauthorized)
            {
                Console.WriteLine("wrong credentials");
            }
            else
            {
                task.Result.EnsureSuccessStatusCode();
                Console.WriteLine(task.Result.Content.ReadAsAsync<string>().Result);
            }
        }
    }
}